The present invention relates to the art of cleaning, decontaminating, and sterilizing medical instruments and devices. It finds particular application in conjunction with the cleaning, decontamination, and sterilization of previously used catheters, such as percutaneous transluminal coronary angioplasty catheters (PTCA catheters), for subsequent reuse and will be described with particular reference thereto.
As the costs associated with the delivery of effective healthcare continue to rise, there is a continuing effort on the part of doctors, healthcare facilities, and insurers to find ways of reducing these costs. The increasing popularity of single-use disposable medical devices has contributed to the increasing costs of surgery. The PTCA catheter is a widely used single-use disposable medical device used by surgeons to perform percutaneous transluminal angioplasty, a surgical procedure to clear blockages of plaque and the like from the arteries of a patient.
A percutaneous transluminal coronary angioplasty is carried out utilizing a PTCA catheter which typically takes the form of a balloon and a balloon lumen having a coaxial guide wire lumen passing therethrough. The proximal end of the PTCA catheter is bifurcated and includes a guide wire lumen port providing access to the guide wire lumen and a balloon lumen port providing access to the balloon lumen, and thus, the balloon. The distal end of the PTCA catheter includes the closed balloon which is sealed around the open end of the guide wire lumen, i.e., the guide wire lumen passes through the balloon and is open at its distal end. The surgeon uses a guide wire to guide the PTCA catheter into the vascular system of the patient to an area where a blockage exists. The catheter is often inserted into the femoral artery of the patient, and therefore, the catheter must be of a significant length (often 150 centimeters) to reach areas near the patient's heart.
After the catheter is in position, the surgeon inflates the balloon with a fluid, such as saline, by injecting the saline into the balloon lumen port of the catheter. Often, the saline includes a radiographic dye which enables the position and the inflated profile of the balloon to be monitored radiographically. The balloon expands radially and thus forces the arterial plaque radially outward into the wall of the artery. The surgeon then deflates the balloon, withdraws the catheter from the patient's vascular system, and disposes of the catheter.
Usually, more than one catheter is used on a particular patient, at a cost of several hundred dollars or more per catheter. Thus, a significant cost savings could be realized from the reuse of PTCA catheters. One difficulty associated with cleaning and sterilizing catheters such as PTCA catheters is attributable to a combination of the length of the catheter, the narrowness of the catheter and the guide wire and balloon lumens, and the closed balloon at the distal end of the catheter which does not allow liquid sterilant to be flushed through the balloon lumen and the balloon.
The cleaning of these devices by hand is time consuming and unreliable. Prior attempts to automate the process have resulted in unduly complex systems that have not been proven to be effective. Prior systems rely solely on liquid sterilization and are not compatible with gas sterilization techniques such as the use of ethylene oxide gas (EO) and these prior systems specifically teach away from the use of EO. Even with respect to the liquid sterilization utilized in the prior systems, the methods and apparatus disclosed do not control the "contact time" of the cleaning agent and the sterilant within the balloon and balloon lumen. They require the balloon to be pressurized with liquid sterilant and a cleaning agent an excessive number of times, reducing the remaining useful life of the balloon. Furthermore, merely filling the balloon lumen and balloon with a cleaning agent and sterilant and immediately flushing the same therefrom a selected amount of times, without further controls, has been found to be an ineffective cleaning and sterilization technique in certain circumstances.
One prior PTCA catheter sterilization method requires the liquid sterilized catheter to be rinsed of liquid sterilant immediately prior to use. This prior method requires a nurse or a surgical assistant to rinse the balloon and balloon lumen by injecting several syringes or more of sterile saline into the balloon. The saline that drains from the balloon and balloon lumen must be tested for the presence of sterilant using chemical test strips. The rinsing must be continued in this manner until the test strips indicate that the concentration of sterilant in the evacuated rinse fluid is below safe thresholds. It can be seen that the foregoing PTCA catheter sterilization method is time consuming and inconvenient. Also, the rinsing of the catheter just prior to its use results in a wet catheter being presented to the surgeon, which some surgeons may find objectionable.
Another disadvantage of known catheter sterilization systems is their requirement that a single catheter be processed or sterilized and stored in a specially designed cassette while awaiting use. These cassettes must be specially pressurized and capped in order for them to maintain the sterility of the catheter. Also, each cassette holds only one catheter, and thus, the efficiency of this prior system is necessarily limited.
The present invention provides a new and improved catheter cleaning, decontamination, and sterilization method and apparatus which overcomes the above-referenced problems and others.